All animals are unique, presenting a wide range of evolutionary features, like large ears, long noses, and hollow bones. Humans are singular because they seem to lack many of the features common to most animals. Features like tails and a covering of hair, scales, or feathers are nearly universal across the animal kingdom. These are things that are clearly absent in humans.
If you take a closer look though, the human body has a lot of hints of how we’ve changed, evolving from a look that was much more similar to other animals into the very unique creature we are today.
What Is the Evidence of Evolution on the Human Body?
Mostly, you’ll need be looking at organs and body parts with either no obvious purpose or that don’t get used anymore. Many of these exist in other animals, making it clear how they are used, hinting at how we probably used them before we evolved to no longer need them.
1. You may not have a tail, but you have a tailbone.
One of the most obvious differences between humans and the vast majority of animals is that we don’t have tails. If you’ve ever had the misfortune of falling while skating, rollerblading, or moving too fast and found yourself falling backward, you do have a tailbone. And that thing is pretty sensitive when you land on it.
There are actually a number of other tailless animals, such as gorillas and orangutans. They are humanity’s closest relatives in the animal kingdom, and like humans, they don’t spend a lot of time in the trees. More importantly, they walk standing more upright than a majority of other animals. This is why they don’t have tails, just like humans.
However, evolution hasn’t quite gotten rid of all of the evidence that humans and the great apes once had tails. The extra vertebrae at the end of your spine make up the coccyx, but we call it the tailbone. That’s not an accident. This small cluster of bones used to be the base for our tails.
2. Check out those goosebumps!
We may not have the kind of thick coat or outer covering that most animals do, but those goosebumps are remnants of the hair we used to have. Whenever you get chilly or get a bad feeling, tiny muscles around your hair follicles contract to create those little bumps. This is the same kind of reaction you see when a cat is scared or a dog gets its hackles up. The difference is that it’s much harder to see on humans now that we have a far less obvious layer of hair.
3. Why else would we have an appendix?
The appendix is probably the best-known organ for causing people to wonder why we even have it. Even today, we aren’t entirely sure what the purpose of this little add-on is. There is some speculation that it plays a role in housing bacterias and other things that make it seem more like a biohazard than an organ. There are also theories that it helps prevent cancer.
And that’s exactly the point. When a patient has their appendix removed, there is no obvious change in the way the patient functions. They just don’t have to worry about the appendix getting infected and rupturing.
Whatever the appendix used to do, it doesn’t seem like it is really necessary anymore.
4. You don’t need to wiggle your ears anymore.
Sure, it is interesting to watch someone who can wiggle their ears, but this is a rarity among humans. That’s because since we now walk upright, we can far more easily turn and look around, meaning we don’t need to rely on our ears picking up all of those little noises that may indicate danger.
Think about your pet or an animal in your neighborhood. Cats, dogs, and rodents all stop and perk up their ears when they hear various sounds. Literally. Their ears actually move and stand up as much as possible (labs, basset hounds, and some other dog breeds don’t have the necessary muscles to hold their ears up).
People aren’t able to do much more than wiggle their ears, and even that is a fairly rare ability. Yet we all have some vestiges of those muscles that give us the ability to move them a little. That’s because we used to need to be able to use our ears like other animals. With the changes in our posture, we didn’t really need that ability anymore, so it gradually went away.
5. We lost our third eyelid, but a bit of it remains.
If you’ve ever looked closely at your eye in the mirror, you probably noticed that there’s a little bit of extra flesh in the corner. This is called the semilunar fold, and it used to be bigger than what you see today.
Many animals have a third eyelid, with reptiles and birds being well-known for this additional component to their eye. This extra eyelid protects their eyes, particularly when they are eating and have to get their faces close to the gore of their feast. The eyelid also helps to clean the eye after those feasts. Just like our remaining eyelids, the third eyelid also helped to keep the eye moist.
Humans are far from the only animal not to have a full third eyelid, but it is still very clear to see where the remnants of it remain in the corner of the eye. It’s not entirely sure why the eyelid has disappeared. Perhaps because we have hands, we don’t have to use our faces in a way that puts them at greater risk of injury or dirt getting into our eyes. Still, it seems like it is the kind of body part where a little redundancy wouldn’t be bad, especially now that people spend so much time staring at screens. An extra eyelid to keep our eyes moist would actually be quite useful.
6. The problematic wisdom teeth are definite signs of our evolution.
This is another body part that has actually become a problem because we simply don’t need them anymore. While evolution has already made it clear that wisdom teeth are probably on the way out, it’s not nearly fast enough for most humans.
We used to need more teeth to better deal with food. Over time, the human brain has continued to grow, requiring more real estate in your head. One of the areas that started shrinking thousands of years ago was the mouth. Now, we are to the point that wisdom teeth typically don’t have adequate room when they finally come in, creating far more problems than help. Since wisdom teeth tend to cause infections and pain, as well as being very hard to floss when they are nearly stacked on top of our molars, people have been pulling them out for decades.
It looks like we are putting those bigger brains to good use, especially when we use medications to numb the pain of removing teeth. It seems like an excellent trade-off that evolution has provided.
7. You may have an extra muscle on your lower leg.
The fact that this muscle, called the plantaris, isn’t universal in humans lets you know that evolution is either adding it or taking it away from humans. If you have the plantaris muscle, it is located in the top part of the lower leg roughly from your knee to your calf. It helps you to bend your knee or flex your ankle a little more easily than people who don’t have it. Based on research, the ease with which you can bend your knee is because the muscle is actually pretty small. So, if you don’t have it, don’t worry. You really aren’t missing out on much.
The real benefit of the plantaris is the tendon that connects it to the bone. It’s the longest tendon in the human body. Since you don’t actually need the muscle, if you have problems with another tendon in your body, this tendon can be used to replace it. It’s kind of like a spare part in your body if you have it, and that’s really the best benefit it offers.
8. Those muscles in your upper lip, they were probably for whiskers.
This variation isn’t nearly so obvious without actually having it pointed out, but the vast majority of mammals have whiskers. Humans are one of three mammals that don’t have them. Anteaters and platypuses also lack whiskers, which tells you how highly specialized animals are that don’t have whiskers.
But our body hides little hints that we used to have whiskers. A long time ago, we probably did need whiskers. They are incredibly useful because whiskers provide a lot of information about the world around you, especially in the dark when your eyes are far less effective. Humans don’t need that kind of help now though. We can hold out our hands and feel much further in front of us in the dark.
We no longer need whiskers because we use senses besides touch to understand the world around us. But we haven’t quite evolved to get rid of everything associated with whiskers. The actual whiskers are gone, but those little muscles around our upper lips are still there. For now.
9. The pyramidalis and sternalis, two muscles you probably don’t have.
This is probably the best example of evolutionary proof on the human body that we have been steadily changing over the millennia. The pyramidalis is located in the lower part of the abdomen, and the sternalis is located at the top of your pectoral muscles (if you have it). Neither of these muscles is obvious to the naked eye.
The pyramidalis is located in your lower abdomen, and 80% of people still have it. Still, nearly a quarter of all humans have already lost this muscle.
The sternalis is located near the collarbone and the pectoral muscles. This one is actually almost entirely gone from the human body, and only about 8% of humans still have it. Like the pyramidalis, this muscle isn’t really visible, so you would need to be specifically checked to see if you have it.
These muscles probably had a lot of use when we didn’t walk upright, but now that we have a vertical posture, they are no longer required. The way these two muscles are clearly going away and have no obvious use today is among the best examples of proof that the human body is evolving and getting rid of unnecessary parts.
10. If you hate hiccups, part of the blame goes to evolution.
Instead of looking at some of the other body parts, let’s take a look at something that is involuntary. Hiccups are annoying, distracting, and potentially painful. There is no clear reason why we get them. There’s no discernible benefit to them, just a range of negative problems caused by them.
Hiccups are the result of your vocal cords closing at the same time. There are animals that actually benefit from this action – Amphibians.
Yep, amphibians need this when they are underwater switching between using their lungs and gills. This is a short stage when the animals have both because they do lose their gills as adults. Their body does something that is similar to a hiccup to force any water out of their body through their gills.
This is the closest tie to our very ancient connection to fish and evolving so that we don’t need gills. Now that’s a very interesting hint about how far the human body has evolved from where it started. It’s made us incredibly unique, but at the same time it ties us to the rest of the animal kingdom.